Easy opening rear seam bags and packaging methods

ABSTRACT

A package bag may be made from a sheet of flexible packaging material that has been folded along a longitudinal direction with the edges of the sheet brought together and sealed to form a longitudinal rear seam. A starter cut has been formed only in the longitudinal seam to facilitate opening the package bag. The package bag may be opened by pulling in opposite directions on the longitudinal seam at points on either side of the starter cut. Such package bags may be made from a sheet of flexible roll stock having one or more notches formed at spaced apart locations along one or more edges of the sheet. When the sheet is folded such that the edges meet and are sealed to form a longitudinal rear seam of a package bag, the notches provide a starter cut for opening the package bag.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional patent application of and claims thebenefit of priority of co-pending U.S. patent application Ser. No.11/009,183, entitled “EASY OPENING REAR SEAM BAGS AND PACKAGINGMETHODS”, filed Dec. 10, 2004, the entire disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to packaging and more particularly to easy openbags and methods of manufacturing such bags.

BACKGROUND OF THE INVENTION

Modern packaging for food and other products often uses sealed bagshaving seams at one or more ends of the bag and an exposed seam thatusually runs the entire length of the rear of the bag. Such bags havebeen conventionally made of a packaging material, such as a syntheticresin film or a laminated material formed by laminating the syntheticresin film and an aluminum foil or the like. The package bag is filledwith a material to be packed, such as liquids, powders or viscousmaterials, before being hermetically sealed.

To open the package bag, therefore, it is common practice for a user ofthe products stored in the bag to cut a sealed portion of the packagefilm as the packaging material with a knife or scissors or break it openwith a fingertip. When the package bag is to be cut with a knife orscissors, the opening procedure is troublesome, as it requires a tool.When the package film is to be ruptured with a fingertip, the opening ofthe package film may not be accomplished easily. Unfortunately, thematerial from which these bags are made and the sealing of the seams canmake the bag difficult to open.

There have been several attempts in the prior art to address the problemof opening sealed package bags. For example, U.S. Pat. No. 6,352,364issued Mar. 5, 2002 to Mobs starts a tear on the side of the bag andthen has the longitudinal seal cut to ease the tear through it. Thisrequires that two cuts be aligned and also requires modification of theend seal.

Similarly, U.S. Pat. No. 6,343,876 issued Feb. 5, 2002 to Takahashi etal describes starting the tear on the side of a pouch that has seamsrunning down each side and no rear seam.

U.S. Pat. No. 6,102,571 issued Aug. 15, 2000 to Moteki et al alsoinitiates the tear from the side of the bag then has a second tear-ablezone for tearing through the rear seam.

U.S. Pat. No. 5,371,997 issued Dec. 13, 1994 to Kopp et al describes along and narrow bag with a longitudinal seam on one side of the bag withthe tear being initiated from the side of the bag.

U.S. Pat. No. 5,067,306 issued Nov. 26, 1991 to Umezawa describes makingmicro cuts on the sides of the bag material as it is being packaged, butmakes no mention of the problem tearing through the rear seam of thebag.

U.S. Pat. No. 4,725,329 issued Feb. 16, 1998 to Tani it uses a tearstring to tear through the rear seam of a package bag. However, a tearstring could be hard to manage on large bags like potato chips.

Thus, there is a need in the art, for an easy opening package bag and amethod for manufacturing it.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, a package bag may be madefrom a sheet of flexible packaging material that has been folded along alongitudinal direction with the edges of the sheet brought together andsealed to form a longitudinal rear seam. A starter cut is formed only inthe rear seam to facilitate opening the package bag. The package bag maybe opened by pulling in opposite directions on the longitudinal seam atpoints on either side of the starter cut.

According to another embodiment of the invention a composition of matteris provided for forming a package bag. This composition of matterincludes a sheet of flexible roll stock having one or more notchesformed at spaced apart locations along one or more edges of the sheet.When the sheet is folded such that the edges meet and are sealed to forma longitudinal rear seam, the notches provide a starter cut only in therear seam for opening package bags formed from the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIGS. 1A-1C are three-dimensional diagram of package bags according toan embodiment of the present invention;

FIG. 2 is a three-dimensional schematic diagram illustrating themanufacture and filling of bags according to another alternativeembodiment of the present invention.

FIGS. 3A-3B are three-dimensional diagrams of rolls of material forforming a package bags according to an alternative embodiment of thepresent invention; and

FIG. 4 is a three-dimensional schematic diagram illustrating themanufacture and filling of bags according to another alternativeembodiment of the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Although the following detailed description contains many specificdetails for the purposes of illustration, anyone of ordinary skill inthe art will appreciate that many variations and alterations to thefollowing details are within the scope of the invention. Accordingly,the exemplary embodiments of the invention described below are set forthwithout any loss of generality to, and without imposing limitationsupon, the claimed invention.

FIG. 1A depicts a package bag 100 according to an embodiment of thepresent invention. The bag depicted in FIG. 1A is a relatively simpletype of bag known as a pillow bag or pillow pouch. The bag 100 isgenerally made from a sheet of flexible packaging material that has beenfolded along a longitudinal direction. The side edges of the sheet havebeen brought together and sealed to form a longitudinal rear seam 102disposed between the sides of the bag. A starter cut 104 has been formedin the rear seam 102 to facilitate opening the package bag. End seams106, 108 close the ends of the package bag 100 to seal products withinit. As a result of the starter cut 104, the package bag 100 may beopened by pulling in opposite directions on the longitudinal seam atpoints on either side of the starter cut.

The rear seam 102 usually lies flat against the package bag 100 but caneasily be lifted to provide finger grab points on both sides of thestarter cut 104. Embodiments of the present invention work with any bagthat has a seam that can be lifted from the bag. During manufacturing ofthe bag the rear seam 102 may be formed perpendicular to the rearsurface of the bag and then folded over to lay flat against the bag.This makes it very handy to pull the seam up and use it to providefinger grab points for tearing the bag open.

In some embodiments, one or more guide strips 105, 107 are placedlaterally across the package bag near the starter cut 104 to guide thetear that results when the rear seam 102 is pulled. The guide strips aremade of tear-resistant material, such as plastic that are formed onto orinto the material of the bag 100. A single guide strip may be used or,as shown in FIG. 1A, two guide strips may be placed close together oneither side of the starter cut to contain the tear between the two guidestrips.

Embodiments of the present invention may be used with other types ofbags having a longitudinal rear seam. Examples of such bags include agusseted bag 110 and a flat bottom bag 120, respectively depicted inFIG. 1B and FIG. 1C. The gusseted bag 110 includes a rear longitudinalseam 112, starter cut 114 and end seams 116, 118 and special folds orgussets that give the bag a substantially rectangular cross-section. Theflat bottom bag 120 includes a rear longitudinal seam 122 and startercut 124 an end seal 126 and folds and seals that provide both arectangular cross section and a flat bottom 128. Such package bags arewell known within the packaging arts. Guide strips, such as thosedescribed above, may also be used with the gusseted bag 110 and/or theflat bottom bag 120.

Package bags of the type described herein may be used to store any typeof products commonly stored in sealed bags. Such products include, butare not limited to snacks, such as potato chips and pretzels, coffee,cheese, produce, candy, frozen foods, sealed medical products such asbandages, tape medicine, detergent, chemical powders, cosmetics amongmany others.

Package bags of the type described herein can be fabricated by a numberof different techniques. Products are often packaged in bags usingvertical form-fill machines or horizontal form-fill machines. Suchmachines form the bags from a continuous sheet of roll stock and fillthem as the bags are fabricated. FIG. 2 illustrates one example, amongothers, of a technique for packaging products in bags of the typedescribed above. In this example, a vertical form-fill system 200 formsthe bags from a sheet of material 202. The sheet may made of anysuitable flexible material used in the packaging industry, examples ofwhich include, but are not limited to, polyethylene (e.g. low densitypolyethylene (LDPE) or linear low density polyethylene (LLDPE),polypropylene, metallocene or laminated film. Examples of suitablelaminated films include polyester/poly, paper/poly, glassine/poly,Bopp/foil/poly and the like. The sheet 202 may be in the form of a rollstock, e.g., a laminated film roll stock or surface printed roll stock.Materials for making bags are available, e.g., from Duralam, Inc. ofAppleton, Wis. and other commercial suppliers.

The sheet 202 is drawn from a roll 204 over a series of rollers to avertical form-fill tube 206. The sheet 202 wraps around the form-filltube 206 and the edges of the sheet 202 are brought together to form thesheet 202 into a tube. A longitudinal sealer device 207 seals the edgesof the sheet 202 together to form the rear seam 208 of a bag 210. An endsealer then seals one end of the bag 210. Typically the edges and endsare sealed by some combination of heat and pressure. After the end issealed the bag 210 is filled through the form-fill tube 206. Then thesecond end is sealed to close the bag 210. A shearing device 212 cutsthe sheet 202 along the end seal to separate the bag from subsequent bagthat is formed from the same sheet material 202. The shearing device 212may leave part of the end seal on the bag 210 and part on the subsequentbag.

The starter cut described above can be made in the rear seam at anypoint in this procedure. For example a notch-cutting device 214, e.g., asliding knife can cut a notch 215 in the rear seam 208 to form thestarter cut. In FIG. 2, the notch-cutting device 214 is located betweenthe longitudinal sealer device 207 and the shearing device 212.Alternatively, the notch-cutting device may be located after theshearing device 212 or at some other convenient point in the system 200.

In an alternative embodiment, the starter cut may be made as part of theproduction of the roll stock used to form the bags. This is particularlyadvantageous in that such a roll stock can be used in an existingform-fill machine without having to modify the machine to make thestarter cut in the rear seam. FIG. 3A depicts an example of a sheet ofmaterial 300 for forming bags that can be used to make package bagsaccording to an embodiment of the present invention. The material 300,e.g., any of the flexible materials described above, may be in the formof a sheet 302 of flexible roll stock which may be wound into a roll 304suitable for use in a form-fill machine. The sheet 302 has first andsecond surfaces 301, 303. One surface 301 typically has no printing andserves as the inside of a bag. The other surface 303, which may haveprinting on it, serves as the outside of the bag. The printing may bedone by conventional equipment, such as that provided by PaperConverting Machine Company of Green Bay Wis. The sheet is cut alonglines indicated by D during forming and filling to separate individualbags from the sheet 302. The sheet 302 may or may not be perforatedalong the lines D to facilitate separate of the bags.

One or more notches 306 are formed at spaced apart locations along oneor more edges 308 of the sheet 302. When the sheet 302 is folded suchthat the edges 308 meet and are sealed to form a longitudinal rear seam,the notches 306 provide a starter cut for opening package bags formedfrom the sheet 302. In some embodiments a single notch is formed alongone edge. In other embodiments, aligned notches 306 are formed in bothedges 308 of the sheet 302. The aligned notches 306 overlap at leastpartially to form a starter cut all the way through the rear seam.

FIG. 3B depicts a material 310 that is a variation on the material 300of FIG. 3A. The material 310 may be in the form of a sheet 312 and maybe wound into a roll 314. The sheet 312 may be made from any suitableflexible bag-making material. The sheet 312 includes guide strips 318formed laterally across the sheet proximate notches 316. In the exampledepicted in FIG. 3B pairs of guide strips 318 are placed close togetherwith a notch 316 between the two guide strips in each pair.Alternatively a single guide strip may be placed such that the notcheslie between a guide strip and a location D where the sheet 312 is to becut to separate one bag from another.

FIG. 4 illustrates one example, among others, of a technique forpackaging products in bags of the type described above using thepre-notched roll stock of the types described in FIGS. 3A-3B. In thisexample, a vertical form-fill system 400 forms the bags from a sheet ofmaterial 402. By way of example, the system 400 may be a Model VPKvertical/form/fill machine from Rovema Packaging USA of Lawrenceville,Ga. In this case, the sheet 402 already has notches 403 in its edges asdescribed above with respect to FIG. 3A as well as lateral guide strips405 as described above with respect to FIG. 3B. The sheet 402 is drawnfrom a roll 404 over a series of rollers to a vertical form-fill tube406. The sheet 402 wraps around the form-fill tube 406 and the edges ofthe sheet 402 are brought together to form the sheet 402 into a tube.The notches on opposite edges of the sheet 402 align and overlap to formthe start cut 401. A longitudinal sealer device 407 seals the edges ofthe sheet 402 together to form the rear seam 408 of a bag 410. An endsealer then seals one end of the bag 410 along the line indicated at D,the bag is filled through the form-fill tube 406 and the second end issealed to close the bag 410. A shearing device 412 may cut the sheet 402along the end seal to separate the bag from subsequent bag that isformed from the same sheet material 402.

Embodiments of the present invention provide for easy opening bags withonly minor modifications to existing packaging equipment and processes.Such easy open bags are more desirable for consumers and relativelyinexpensive to manufacture compared to other types of easy open bags.Although the above discussion mentions vertical form-fill-seal systems,embodiments of the invention are not limited to such systems for makingand filling bags. Other bag filling and sealing systems, such ashorizontal fill machines and those that use pre-made bags, may beadapted to implement embodiments of the present invention.

While the above is a complete description of the preferred embodiment ofthe present invention, it is possible to use various alternatives,modifications and equivalents. Therefore, the scope of the presentinvention should be determined not with reference to the abovedescription but should, instead, be determined with reference to theappended claims, along with their full scope of equivalents. In theclaims that follow, the indefinite article “A”, or “An” refers to aquantity of one or more of the item following the article, except whereexpressly stated otherwise. The appended claims are not to beinterpreted as including means-plus-function limitations, unless such alimitation is explicitly recited in a given claim using the phrase“means for.”

1. A composition of matter for forming a package bag, comprising: asheet of flexible roll stock having one or more notches formed at spacedapart locations along one or more edges of the sheet, wherein, when thesheet is folded such that the edges meet and are sealed to form alongitudinal rear seam, the notches provide a starter cut only in therear seam for opening package bags formed from the sheet of flexibleroll stock.
 2. The composition of matter of claim 1 wherein the one ormore notches are formed along a single edge of the sheet.
 3. Thecomposition of matter of claim 1 wherein the one or more notches areformed in two edges of the sheet.
 4. The composition of matter of claim1 wherein the one or more notches include one or more pairs of alignednotches that overlap at least partially when the sheet is folded suchthat the edges meet.
 5. The composition of matter of claim 1, furthercomprising one or more guide strips formed onto the sheet of roll stock,wherein the guide strips run laterally across the sheet proximate theone or more notches.
 6. The composition of claim 1 wherein the one ormore guide strips include pairs of two closely-spaced guide stripsdisposed such that the starter cut lies between the two guide strips. 7.A packaging method, comprising the steps of: folding a sheet of flexiblepackaging material along a longitudinal direction first to bring firstand second edges of the sheet together; sealing the first and secondedges to form a longitudinal rear seam along the longitudinal direction;and forming a starting cut only in the longitudinal seam to facilitateopening the package bag
 8. The method of claim 7 wherein forming thestarter cut includes, before folding the sheet of flexible packagingmaterial, forming one or more notches in the sheet of flexible packagingmaterial at spaced apart locations along one or more edges of the sheet,wherein, when the sheet is folded to bring the first and second edgestogether and are sealed to form the longitudinal seam, the notchesprovide the starter cut.
 9. The method of claim 7, further comprisingthe step of forming one or more guide strips onto the sheet of flexiblepackaging material, wherein the guide strips run laterally across thesheet proximate the starter cut.
 10. The method of claim 9, wherein theone or more guide strips include two closely spaced guide stripsdisposed such that the starter cut lies between the two guide strips.11. The method of claim 7, further comprising the step of, after foldingthe sheet of flexible packaging material, sealing a first end of thefolded sheet to close a first end of a bag.
 12. The method of claim 11wherein the starter cut is formed before sealing the first end of thefolded sheet.
 13. The method of claim 11, further comprising the stepof, after sealing the first end of the folded sheet to close the firstend of the bag, filling the bag with one or more products.
 14. Themethod of claim 13 further comprising, the step of, after filling thebag with one or more products, sealing a second end of the folded sheetto close a second end of the bag.
 15. The method of claim 13 whereinforming the starter cut takes place before sealing the second end of thesheet or before filling the bag.
 16. The method of claim 7, wherein thesheet of flexible packaging material comprises a sheet of flexible rollstock having one or more notches formed at spaced apart locations alongone or more edges of the sheet, wherein, when the sheet is folded suchthat the edges meet and are sealed to form the longitudinal rear seam,the notches form the starter cut.
 17. The method of claim 16 wherein theone or more notches include one or more pairs of aligned notches thatoverlap at least partially when the sheet is folded such that the edgesmeet.